#include <stdio.h>
/* extern */
 int i = 12;//in a definition, extern could be omitted.
//warning: 'i' initialized and declared 'extern'

/* extern static  */
int j = 1212;
//error: multiple storage classes in declaration specifiers

int main()
{
  printf("i = %+3.3d\n",i);
  int a = i+i;
  return 0;
}
